The invention refers to an electronic component, in particular a current sensor.
These types of current-sense resistors are known, for example from EP 0 605 800 A1 and EP 1 253 430 A1, and allow measurement of an electrical current according to the four-wire technology. In this case, the electrical current to be measured is passed via two contacts through the current-sense resistor while the electrical voltage is measured via two further contacts, which drops over the resistance element of the current-sense resistor. From the voltage measured it is then possible, by applying Ohm's law, to calculate the electrical current which flows through the current-sense resistor.
From EP 1 253 430 A1 it is furthermore known that a measurement value recording system in the form of an ASIC (ASIC: Application Specific Integrated Circuit) is directly arranged on a current-sense resistor so that the current-sense resistor forms a current sense module together with the ASIC. Current measurement using this type of current sense modules offers the advantage of very precise measurement and a low construction size; however, such current sense modules are expensive and are therefore only used for precision applications where a high precision of measurement is important.
In the industrial area there are numerous applications (for example current limit switches, electronic fuses, and others), for which it is only necessary to have a monitoring function in place, whereas the precision of measurement is less important. For some applications it is even desirable that the current measurement only reacts slowly to changes in the current to be measured in order to avoid excessively frequent switching off due to short-term current peaks. It can therefore be desirable that the current measurement reacts to a change in the current to be measured according to a time constant which is in the range of seconds. Furthermore, it should also be possible to measure both a direct current and an alternating current, such as a 50 Hertz alternating current, an alternating current strongly distorted by switching operations, or even a high-frequency alternating current.
Reference is also made to U.S. Pat. No. 3,026,363 concerning the prior art. This patent discloses a component for measurement of the temporal average of an electrical signal, such as a broadband signal. Here there is indeed a temperature measurement made by means of a thermoelement but the temperature difference between the resistance element and its connection parts is not measured.
Furthermore, a current-sense resistor is known from DE 10 2004 062 655 A1 for which the heating up of the current-sense resistor and the resultant change in the resistance value is taken into account in order to avoid temperature-dependent measurement errors. In this regard too, however, the temperature difference between the resistance element and its connection parts is not measured. This patent application therefore just discloses temperature compensation for a current-sense resistor.
Finally, regarding the general technical background, one is referred to US 2004/0227522 A1 and US 2010/0040120 A1.
The object of the invention is therefore to create another option for current measurement which is less costly to produce and also, preferably, avoids the above-mentioned disadvantages.
This object is achieved by a current sensor according to the invention.